# Copyright (C) 2020 Felix Lechner
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, you can find it on the World Wide
# Web at https://www.gnu.org/copyleft/gpl.html, or write to the Free
# Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
# MA 02110-1301, USA.

package Test::Lintian::Filter;

=head1 NAME

Test::Lintian::Filter -- Functions to select with tests to run

=head1 SYNOPSIS

  use Test::Lintian::Filter qw(find_selected_lintian_testpaths);
  my @testpaths = find_selected_lintian_testpaths('suite:changes');

=head1 DESCRIPTION

Functions that parse the optional argument 'only_run' to find the
tests that are supposed to run.

=cut

use v5.20;
use warnings;
use utf8;

use Exporter qw(import);

BEGIN {
    our @EXPORT_OK = qw(
      find_selected_scripts
      find_selected_lintian_testpaths
    );
}

use Carp;
use Const::Fast;
use File::Spec::Functions qw(rel2abs splitpath catpath);
use File::Find::Rule;
use List::SomeUtils qw(uniq none);
use List::Util qw(any all);
use Path::Tiny;
use Text::CSV;
use Unicode::UTF8 qw(encode_utf8);

use Lintian::Profile;
use Test::Lintian::ConfigFile qw(read_config);

my @LINTIAN_SUITES = qw(recipes);

const my $EMPTY => q{};
const my $SPACE => q{ };
const my $VERTICAL_BAR => q{|};
const my $DESC => 'desc';
const my $SEPARATED_BY_COLON => qr/([^:]+):([^:]+)/;

=head1 FUNCTIONS

=over 4

=item get_suitepath(TEST_SET, SUITE)

Returns a string containing all test belonging to suite SUITE relative
to path TEST_SET.

=cut

sub get_suitepath {
    my ($basepath, $suite) = @_;
    my $suitepath = rel2abs($suite, $basepath);

    croak encode_utf8("Cannot find suite $suite in $basepath")
      unless -d $suitepath;

    return $suitepath;
}

=item find_selected_scripts(SCRIPT_PATH, ONLY_RUN)

Find all test scripts in SCRIPT_PATH that are identified by the
user's selection string ONLY_RUN.

=cut

sub find_selected_scripts {
    my ($scriptpath, $onlyrun) = @_;

    my @found;

    my @selectors = split(m/\s*,\s*/, $onlyrun//$EMPTY);

    if ((any { $_ eq 'suite:scripts' } @selectors) || !length $onlyrun) {
        @found = File::Find::Rule->file()->name('*.t')->in($scriptpath);
    } else {
        foreach my $selector (@selectors) {
            my ($prefix, $lookfor) = ($selector =~ /$SEPARATED_BY_COLON/);

            next if defined $prefix && $prefix ne 'script';
            $lookfor = $selector unless defined $prefix;

            # look for files with the standard suffix
            my $withsuffix = rel2abs("$lookfor.t", $scriptpath);
            push(@found, $withsuffix) if -e $withsuffix;

            # look for script with exact name
            my $exactpath = rel2abs($lookfor, $scriptpath);
            push(@found, $exactpath) if -e $exactpath;

            # also add entire directory if name matches
            push(@found, File::Find::Rule->file()->name('*.t')->in($exactpath))
              if -d $exactpath;
        }
    }

    my @sorted = sort +uniq @found;

    return @sorted;
}

=item find_selected_lintian_testpaths(TEST_SET, ONLY_RUN)

Find all those test paths with Lintian tests located in the directory
TEST_SET and identified by the user's selection string ONLY_RUN.

=cut

sub find_selected_lintian_testpaths {

    my ($testset, $onlyrun) = @_;

    my $filter = {
        'tag' => [],
        'suite' => [],
        'test' => [],
        'check' => [],
        'skeleton' => [],
    };
    my @filter_no_prefix;

    if (!length $onlyrun) {
        $filter->{suite} = [@LINTIAN_SUITES];
    } else {

        my @selectors = split(m/\s*,\s*/, $onlyrun);

        foreach my $selector (@selectors) {

            foreach my $wanted (keys %{$filter}) {
                my ($prefix, $lookfor) = ($selector =~ /$SEPARATED_BY_COLON/);

                next if defined $prefix && $prefix ne $wanted;

                push(@{$filter->{$wanted}}, $lookfor) if length $lookfor;
                push(@filter_no_prefix, $selector) unless length $lookfor;
            }
        }
    }

    my $profile = Lintian::Profile->new;
    $profile->load(undef, undef, 0);

    my @found;
    foreach my $suite (sort @LINTIAN_SUITES) {

        my @insuite;
        my $suitepath = get_suitepath($testset, $suite);

        # find all tests for selected suites
        if (any { $_ eq $suite } @{$filter->{suite}}) {
            push(@insuite, find_all_testpaths($suitepath));
        }

        # find explicitly selected tests
        foreach my $testname (@{$filter->{test}}) {
            my @withtests = find_testpaths_by_name($suitepath, $testname);
            push(@insuite, @withtests);
        }

        # find tests for selected checks and tags
        if (scalar @{$filter->{check}} || scalar @{$filter->{tag}}) {

            my %wanted = map { $_ => 1 } @{$filter->{check}};

            for my $tag_name (@{$filter->{tag}}) {

                my $tag = $profile->get_tag($tag_name);
                unless ($tag) {
                    say encode_utf8("Tag $tag_name not found");
                    return ();
                }

                if (none { $tag_name eq $_ } $profile->enabled_tags) {
                    say encode_utf8("Tag $tag_name not enabled");
                    return ();
                }

                $wanted{$tag->check} = 1;
            }

            for my $testpath (find_all_testpaths($suitepath)) {
                my $desc = read_config("$testpath/eval/" . $DESC);

                next
                  unless $desc->declares('Check');

                for my $check ($desc->trimmed_list('Check')) {
                    push(@insuite, $testpath)
                      if exists $wanted{$check};
                }
            }
        }

        # find tests for selected skeleton
        if (scalar @{$filter->{skeleton}}) {

            my %wanted = map { $_ => 1 } @{$filter->{skeleton}};

            for my $testpath (find_all_testpaths($suitepath)) {
                my $desc = read_config("$testpath/build-spec/fill-values");

                next
                  unless $desc->declares('Skeleton');

                my $skeleton = $desc->unfolded_value('Skeleton');
                push(@insuite, $testpath)
                  if exists $wanted{$skeleton};
            }
        }

        # guess what was meant by selection without prefix
        for my $parameter (@filter_no_prefix) {
            push(@insuite,find_testpaths_by_name($suitepath, $parameter));

            if ($parameter eq 'legacy'
                || exists $profile->check_module_by_name->{$parameter}) {

                push(@insuite,
                    find_testpaths_by_name($suitepath, "$parameter-*"));
            }
        }

        push(@found, sort +uniq @insuite);
    }

    return @found;
}

=item find_all_testpaths(PATH)

Returns an array containing all test paths located under PATH. They
are identified as test paths by a specially named file containing
the test description (presently 'desc').

=cut

sub find_all_testpaths {
    my ($directory) = @_;
    my @descfiles = File::Find::Rule->file()->name($DESC)->in($directory);

    my @testpaths= map { path($_)->parent->parent->stringify }@descfiles;

    return @testpaths;
}

=item find_testpaths_by_name(PATH, NAME)

Returns an array containing all test paths with the name NAME
located under PATH. The test paths are identified as such
by a specially named file containing the test description
(presently 'desc').

=cut

sub find_testpaths_by_name {
    my ($path, $name) = @_;

    my @named = File::Find::Rule->directory()->name($name)->in($path);
    my @testpaths= grep { defined }
      map { -e rel2abs('eval/' . $DESC, $_) ? $_ : undef } @named;

    return @testpaths;
}

=item find_all_tags(TEST_PATH)

Returns an array containing all tags that somehow concern the test
located in TEST_PATH.

=cut

sub find_all_tags {
    my ($testpath) = @_;

    my $desc = read_config("$testpath/eval/" . $DESC);

    return $EMPTY
      unless $desc->declares('Check');

    my $profile = Lintian::Profile->new;
    $profile->load(undef, undef, 0);

    my @check_names = $desc->trimmed_list('Check');
    my @unknown
      = grep { !exists $profile->check_module_by_name->{$_} } @check_names;

    die encode_utf8('Unknown Lintian checks: ' . join($SPACE, @unknown))
      if @unknown;

    my %tags;
    for my $name (@check_names) {
        $tags{$_} = 1 for @{$profile->tag_names_for_check->{$name}};
    }

    return keys %tags
      unless $desc->declares('Test-Against');

    # read hints from specification
    my $temp = Path::Tiny->tempfile;
    die encode_utf8("hintextract failed: $!")
      if system('private/hintextract', '-f', 'EWI', "$testpath/hints",
        $temp->stringify);
    my @lines = $temp->lines_utf8({ chomp => 1 });

    my $csv = Text::CSV->new({ sep_char => $VERTICAL_BAR });

    my %expected;
    foreach my $line (@lines) {

        my $status = $csv->parse($line);
        die encode_utf8("Cannot parse line $line: " . $csv->error_diag)
          unless $status;

        my ($type, $package, $name, $details) = $csv->fields;

        die encode_utf8("Cannot parse line $line")
          unless all { length } ($type, $package, $name);

        $expected{$name} = 1;
    }

    # remove tags not appearing in specification
    foreach my $name (keys %tags) {
        delete $tags{$name}
          unless $expected{$name};
    }

    # add tags listed in Test-Against
    my @test_against = $desc->trimmed_list('Test-Against');
    $tags{$_} = 1 for @test_against;

    return keys %tags;
}

=back

=cut

1;

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